Neutralization of Reactive Oxygen Species at Dinuclear Cu(II)-Cores: Tuning the Antioxidant Manifold in Water by Ligand Design

Abstract

Dinuclear Cu2(II,II)-cores stabilized by the N3O donorset of HL1 = (2-{[[di(2-pyridyl)methyl](methyl)amino]methyl}phenol), HL2 = 2-({[di(2-pyridyl)methyl]amino}methyl)phenol), and HL3 = 2-({[di(2-pyridyl)methyl]amino}methyl)-4-nitrophenol display a unique superoxide dismutase (SOD) combined with catalase (CAT)-like activity in water, at neutral pH. The Cu2L12 < Cu2L22 < Cu2L32 structure-reactivity trend puts a spotlight on the electron-deficient core of Cu2L32 that exhibits the highest SOD (log kcat(O2-) = 7.55) and CAT-like (kH2O2 = 0.66 M-1 s-1) performance. Time-lapse ESI-MS and EPR experiments indicate that a dimeric core is essential for oxygenic turnover upon H2O2 decomposition.